Differential driving and steering mechanism



Sept. 5, 1950 w. G. VAN vooRHls DIFFERENTIAL DRIVING AND STEERING MEcEANIsM Filed Jan. 2s, 1947 2 Sheets-Sheet 1 l I I Ey. I

Fiyi 2 BYl TfOP/VEYS 2f Sheets-Sheet 2 n.

W. G. VAN VOORHIS DIFFERENTIAL DRIVING AND STEERING MECHANISM Sept. 5, 1950 Filed Jan. 23, 1947 IN V EN TOR.

n. w M mm W Patented Sept. 5, 1950 DIFFERENTIALDRIVINGAN D "STEERING MECHANISM William G. QVan Voorhis, ,Columbus, Ohio, Y-assignor to -The Jaeger; Machine Company; VColumbus, .0hio,.,aY corporation oflOho ApplotimrJanuar 23, 1947; Serial N0.i"?723,710

` 8 Claims. (Cl. 74-664) Myanvention rela-tes touiifeientiardrivingiand 'steering mechanism. `Ithastoido, more particularly, vwith differential Tdriving and 'steering mechanism for power-driven vehicles.

hicles in-use at the present time wherein vsteering is accomplished without the use of *steering Wheels" and' associated` steering gear, but by the use of differential-dri'vingv mechanism or `independent clutches for driving the traction-means at opposite sidesof 'theima'chine at different relative speeds. AIhesefvehicles' -include the following types andpthersr' :fu'll crawlers at-'eachfsideiof the machine; driving wheels,- either single drive or tandem; cnr-both sides; half crawlers for driving purposesonboth sides and at orie'end of themachine' and'one ormore' caster or steeringwhe'els at the otherend; anddriving/ wheels; either single driveor tandem, on' 'bothsides-and at one end of the" machine; and lone -or' more caster orvv steering wheels at the-other end. For example; suchmachines may -be `designed as fullcrawler tractors, ditching machines, crawlermounted compressors, crawler mounted shovels,r rubberetired shovels, military tanks, amphibious army fv'ehicles, heavy cargoI transport vehicles, lumber hauling machines, road-paving machines; etc.

- One ofV the objects of my invention is to` provideidriving mechanism for the traction members of a power-driven vehicle of the type wherein the 'steering is accomplishedf'by driving such tractionr members' onvopposite sides of the vehicle at differential speeds lthereby eliminating the necessity ofv'providing asteering wheel and associated steering gear, such driving mechanism-*being so designed thatv the finest deviation from the `line of travel of the'vehicle lto the right or tothe left can 'Deniade at the will of the operator,

Another object of my inventionl is to provide differential driving mechanismv for the traction members -ofa vehicle of the type yindicated alcove whichis such 'that complete alooutLface` turns can be "made'readily during a very short interval and in aminimum amount of space.

Another object of my invention is to provide a differential driving mechanism 4for the traction members'of a vehicle of the type indicated which is such that power may be applied equally to the traction members on opposite 'sides of the vehicle to drive them in the same -directionat the same speed; power may'lbeapplied to-such traction members to drive 'theme inthe same directionat different relative'- speeds; or power fmay :he-f` appliedlto; such .traction members` to drive the VAones atfopposite sidesirropposite directions.

:"Andtheriobject =of`rmy vinvention is toc-.fprovide drivingf mechanism 4of the typel .indicated :above whereby fullpower can I'loef applied to the traction memhersion` oppositeffsidesoi the vehicle not` only to"A drive ithemaequallyi1ini thei' same'directionvto propelf'the machinefhut also to drive .themnroppositef edirections for turning :the vehicle' completely -1 around under unfavorable conditions and under close space'limitations.

:":AfurtherJ-objectrof'my inver'i'tion is to' provide driving mechanism'Y of. the'. type indicatedcincluding :imeans lwhereby i effective retraction braking forcefcan loefy appliedfreadilyfforstopping thevehicle.

lVarious: otherlobjects willbe apparent.

in itsfzpreferredr form, Irprovide aidifferential driving "and `steering `iunit fwhichihas 1an linput shaft that-.;is'idriverrfrcmatsuitablezpower unit. The. connection:fromv the powerfunitf to' my-runit preferablyV includes' acmasterrclutch;andaa suitable forward andfreverse'.` or'imultiplef 'speedl forward-and reversectransmission, My uniii isoprovidedf with 't a, "p'air f :`r of ioutput f shafts ',which""wfil1 drivei the' traction members s on 1 oppositeV sides? of the vehicle. The: two: output e Shafts, `:have'f` ai? dif ferentialfofi'thexzusual type associated therewith Ai'so, eachzof' the' 'shafts'has' a.' direct drive associated therewith lwhich:byapasses" the'diiferential, such @direct drives serving 1 to drive 1' the 'ouput shats in'y opposite. directions. f Ir provide a" 'clutch arrangement infmyfunitfwhichimaylbe selectively actuated-whereby theidr-iveto the output shafts willsbe either through the differential Orl-through the:y direct :drives --fSuchclutch'` arrangementcan either be positive f as described hereinafter Aor `it cano-beV of: the" friction-,type the latterisipreferred. "i If' the .output shafts 2 are :connectedfto traction :member-sionir opposite- `sides r -of` `the vehicle; suchomembersnwill lbe V.driven 1in the 1 'same directionvvhenthe differential 'drive 'is usedland in'v opposite'directions: whenl the Idirect `drives"-are used. I-'iprovidefl al` brakexasso'ciatedwith' each of the output shafts, whereby 2 a braking? force can belappliedi toceitheri'of the shaftsf -tof per-mitdifferential-i'speedsl ofi. .the tracti'onffmemlcersiy atropposite: 'sides of the `vehicle whenf' 'the'dilferential drive'slsiused,ror"can"wbe`applied toiboth of such shafts to exert al braking. action oni the ytraction memberston-ehoth.L sides f ofthe vehicle-whether the differential orthedirectfdrives-are'in use.

:The i foregoing and# otheri 4objects andfadvantages' ofI the present' 'invention will -appearfrom the i following i description 'and Iappended lclaims Whencconsidered' -in"connection with' thesaccom panyingzdrawings `forming-,a "partf 'the specifica- 3 tion wherein like reference characters designate corresponding parts in the several views and wherein:

Figure 1 is a side elevational view of a vehicle to which my invention is applied.

Figure 2 is a plan view of the vehicle.

Figure 3 is a horizontal sectional view taken through a driving unit, constructed according to my invention, along line 3 3 of Figure 1.

Before explaining in detail the present invention, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings since the inven-V tion is capable of other embodiments and of being practiced or carried out in Various ways. It is to be understood also that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

In Figures 1 and 2, I illustrate a tractor I as an exampleof a vehicle to which my driving unit 2 may be applied. The unit 2 will serve to drive, through the chain and sprocket drives 3 or other suitable drives, the traction members 4 and 4a on opposite sides of the Vehicle I. These traction members 4 and 4a are shown as being in the form of crawler units but, as previously indicated, may be of various other types. My unit 2 is driven from the power unit 5 of the vehicle I by a suitable driving connection which may include a master clutch actuated by a pedal 6 and a forward and reverse or multiple forward and reverse transmission actuated by a lever l.

My driving unit 2 is illustrated in detail in Figure 3. It comprises a housing 3 made of suitable cast or fabricated sections bolted together. In the forward wall of the housing a ball bearin'g 9 is mounted and rotatably carries the input shaft I which projects forwardly from the housing. The projecting end of the shaft I9 has a flanged driving'coupling II' keyed thereon and which is used in coupling the shaft I 9 to the driven shaft of the main transmission. A pinion unit I2 is splined on the shaft I0, within housing 8, for axial movement and the pinion portion I3 thereof is adapted to be brought into and out of engaging relationship with a pair of pinions I4 disposed on diametrically opposed sides of the shaft I The pinions I4 are keyed on the forward ends of shafts I which are disposed in spaced parallel relationship to shaft I 9 and whose forward ends are mounted in ball bearings I'B, in the forward wall of the housing 8, and whose rear ends are mounted in a ball bearing I'I Suitably-supported by the housing.

The slidable pinion unit I2 is provided with a female dental clutch member I8, formed on the rear side thereof, which is adapted to receive the male dental clutch member I9 on the forward end of a bevel pinion 2U. This pinion 2l) is rotatably mounted on shaft I U but is not slidable axially thereon. In the neutral position of unit I2, asshown in Figure 3, the pinion I3 is disengaged from the pinions I4 and the clutch member I9 is disengaged from member I9. If unit I`2 is moved forwardly on shaft I9', the pinions I4 will be engaged and driven by pinion I3.v On the other hand, if unit I2 is moved rearwardly, clutch member I8 will engage member I9 and pinion 20 will be driven with shaft IU.

The shaft I0 extends rearwardly through pinion 20 and its rear end is rotatably mounted in` a roller bearing 2I carried by a bracket 22 which is formed as an integral part of the forwardly extending wall 23 which is integral with the back 4 wall of the housing. A similar wall 24 is provided in spaced relationship to wall 23 and both of these walls are provided with axially aligned outlets for receiving the roller bearings 25. These roller bearings receive the sleeve-like ends 26 of the rotatable case of a differential unit 2l. This unit 2! will not be described in detail as it is the usual type of automotive differential. It is provided with a large exterior ring gear 2S which is bolted to the housing and which is engaged by the pinion 20.

Extending from opposite ends of the differential unit 21 are the two output shafts 29. The unit 21 serves to drive these shafts in the usual Way. These shafts extend outwardly through bearing unit 3i! which are associated with the side walls of housing 8.

Keyed on each of the shafts 29 between the wall 23 or 24 and the outer side wall of the housing 8 is a bevel gear 3I. Each of the gears 3f is engaged by the associated bevel pinion 32 which is carried on the rear end of the shaft I5. The extreme outer end of each of the shafts 29 has a brake drum 33 keyed thereon. This brake drum has a sprocket 34 formed integral therewith at the inner side thereof. The sprockets 34 form part of the chain and sprocket drives 3 to the crawlers 4 and 4a. Associated with each of the drums 33 is a contractible brake band 35. A suitable control including a pedal 36 (Figures 1 and 2) may be provided for actuating each of the brake units independently of the other. A lever 3l may be provided for moving the pinion unit I2 and may be suitably connected thereto.

In the operation of the unit 2, when it is dcsired to propel the vehicle under conditions where only slight deviations to the right or to the left of the line of travel are required, the master clutch is disengaged by the pedal 5 and the pinion unit I2 is moved by means of handle 3l to cause clutch members I3 and I9 to be engaged. Then the master clutch is again engaged to drive shaft I The drive to output shafts 29 from input shaft l!) will then be through pinion 29, gear 28, and the differential 21. The differential equally divides the torque of the gear 29 and delivers half of this torque to each of the shafts 29 in the conventional manner. Under these conditions the bevel gears 3l drive the bevel pinions 32 on shafts I5 and the pinions I4 carried by such shafts. Thus, members 3l, 32, I5, and I4 are merely idle and perform no function under these conditions. By this arrangement, the shafts 29 drive the crawlers 4 and 4a through the medium of the sprockets 34; If it is desired to make a slight deviation in the line of travel, one of the brakes is applied by operating a pedal 35 to contract the band 35 around the drum 33 and the crawler 4 at that side of the vehicle will move slower. At the same time, the crawler 4a will move faster. This will cause the vehicle to turn toward the side where the slower moving crawler 4 is located. Greater pressure on the brake which is being actuated causes a sharper turn, the degree of turn increasing as the brake pressure increases up to the maximum limit, which is controlled by the ability of the crawler 4 at one side of the machine to turn the vehicle against the resistance of the crawler which is being braked, plus the resistance of both crawlers to rotation in a horizontal plane.

Should it be desired to make a direct turn within a radius of the vehiclcs own length, the master clutch is disengaged by pedal E and the Slidable pinion unit I2 is then shifted to cause clutchcmembers I8 and I9i to^be disengaged and pinion l3'ltoengage lpinions {4,after whichY the master clutch is again engaged. Powernew is applied from input shaftV l,'through pinion i3, pinions i4, shafts idf-pinionstzand gears-3i to 'the-output shafts 29. Thus, sprockets 34 will be rotated'to'fdrive crawlers 4 and'a. Howeven thecrawlers -will 'be drivenv in opposite directions because the shafts; IEtwillbe rotated in the same directions but since the bevel gears 3| are mounted one to the left and one to the right, respectively, ofthe pinions e2 with `which they mesh, the output shafts 29 will be driven in opposite directions. This will produce the sharpest possible turn for this type of vehicle.

It will be apparent from the above that I have provided a driving unit which is particularly useful on a vehicle having no steering wheel or associated steering gear, for driving the propelling means on opposite sides of the vehicle in opposide directions for extremely short turns, together with means for differentially driving such propelling means in the same direction for making slight turns, With my unit, power is received at a single point and is converted into power delivered at two output points, the relative speed of rotation of the two output points being controllable from a condition of equal rotating speed in the same direction to a condition where one is stationary and the other travels at twice the equalined speed as well as providing all the intermediate ratios between these two extremes; or the two output points may travel at the same speed but in opposite directions. Another advantage of my unit is the flexibility of gear reduction ratios which can be incorporated therein. For example, a conventional 6 to 1 ratio could be incorporated in the unit for driving through the differential while a 10 to 1 or even 20 to 1 ratio could be embodied in the direct opposed drives. This is very important since a great deal more driving power is required on the traction members Iwhen mal-:ing a sudden about-face turn, particularly when such members are partly mired down.

Various other advantages will be apparent.

Having thus described my invention, what I claim is:

1. A driving unit comprising an input shaft, a pair of output shafts, a differential drive associated with said output shafts for driving both of said shafts in the same direction, a driving connection between said input shaft and said diiferential drive adapted to be selectively actuated to drive the differential drive, a positive driving connection between each of said output shafts and said input shaft, said positive driving connections serving to drive one of the output shafts in one direction and the other in an opposite direction, and a connecting mechanism for selecting either the said driving connection of the differential drive or the direct drives for said output shafts, said connecting mechanism being the sole connection between said driving connection of the differential drive and said input shaft and between said positive drives'and said input shaft and including a single shiftable member which in one position directly drives the said driving connection of the differential drive, in another position directly drives both of said positive drives and in an intermediate neutral position interrupts the said driving connection of the differential drive and the positive drives.

2. A unit according to claim 1 including a brake associated with each of said output shafts.

' l' 3.;=A f-drivi-ng V*unit e comprising fr an" inputf: shaft and* a fparirofl` output lshafts `disposedi in. angular relationship, Lea differentiall unit connected between'adjacent endsiofl said outputv shafts, a pinion carried freelyionlsaid'inputshaft and v'driving said/differential unit, a 'slidable Apinion unit ron saidin-put shaft carrying a clutch portion adapted to engage with a clutch lporticnlon said Vfirst pinion f and also carrying a- =pinionportion, a positive drive for each of said output shafts, said positive drives including a^pairof pinions associated with said-.inputi shaft, said-,f` slidablefpinionmunit :being movable to a position where ithetpinionfportion thereof engages-fboth .-of.said last-named pinions or to a position where the clutch portion thereof engages the clutch portionof said first pinion, one of"said"positive"drives lincluding lgearing which drives its-"outputrshaft 'in one direction'and the other of said positive drives including gearing which drives its output shaft in an opposite direction.

4. A driving unit according to claim 3 wherein each of said output shafts has a friction type brake associated therewith which can be operated independently.

5. A driving unit comprising an input shaft and a pair of output shafts, said output shafts having their inner ends adjacent each other and having a differential unit associated therewith, said differential unit including a driving gear, said input shaft being disposed substantially at right angles to said output shafts, a pinion carried rotatably on said input shaft and engaging the driving gear of said differential unit, a driving gear keyed to each of said output shafts, driving units including gearing for driving the two driving gears carried by the output shafts in opposite directions, driving pinions for driving said driving units, said driving pinions being disposed with their axes parallel to said input shaft, and a slidable pinion unit on said input shaft having a clutch portion for engaging a mating clutch portion on said first-named pinion and a pinion portion for engaging both of said driving pinions, said slidable pinion unit being shiftable to a position where the said two clutch portions are engaged or to a position where the pinion portion thereof engages the two driving pinions.

6. A driving unit comprising an input shaft and a pair of output shafts, said output shafts having their inner ends adjacent each other and having a differential unit associated therewith, said differential unit including a driving gear, said input shaft being disposed substantially at right angles to said output shafts, a pinion carried rotatably on said input shaft and engaging the driving gear of said differential unit, a driving bevel gear keyed to each of said output shafts on opposite sides of said differential unit and facing each other, a pair of driving shafts disposed parallel to said input shaft in spaced relationship thereto on opposite sides thereof and each having a bevel pinion on one end engaging the face of one of said bevel gears, a driving pinion on the opposite end of each of said driving shafts, and a slidable pinion unit on said input shaft having a clutch portion for engaging a mating clutch portion on said first-named pinion and a pinion portion for engaging both of said driving pinions, said slidable pinion unit being shiftable to a position where the said two clutch portions are engaged or to a position where the pinion portion thereof engages the two driving pinions.

v 7. A driving unit according to claim 6 inc1uding an independently operable friction brake associated with each of said output shafts.

8. A driving unit according to claim 6 for driving the traction members on opposite sides of a vehicle, including a driving connection between each of said output shafts and the associated traction members of the vehicle.

WILLIAM G. VAN VOORHIS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date y1,205,184 Frederickson Nov. 21, 1916 1,290,266 McEwen Jan. 7, 1919 Number Number Name Date Johnson Sept. 28, 1920 Folse et a1 Sept.' 12, 1922 Saives Mar. 24, 1931 Lamb July 27, 1937 Holtz Mar. 28, 1939 Stegmeier Sept. 8, 1942 Tomik Feb. 5, 1946 FOREIGN PATENTS Country Date Great Britain June 30, 1920 

